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26052 Infliximab Quantitation with Reflex to Infliximab Abs, Serum (INFXR)

Infliximab Quantitation with Reflex to Infliximab Abs, Serum (INFXR)
Test Code: INFXRSO
Synonyms/Keywords
Remicade, Janssen Biotech, Anti-TNF inhibitor, Auto-immune disease treatment, Inflectra, Pfizer, Inc.
Test Components
Infliximab will be performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on all samples. When Infliximab results are below 5.1 mcg/mL, testing for antibodies to infliximab will be performed at an additional charge.
Useful For
Trough level quantitation for evaluation of patients with loss of response to infliximab and infliximab-dyyb
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Red Top Tube (RTT) ​1 mL ​0.5 mL ​
Collection Processing Instructions

​For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Draw blood immediately before next scheduled dose (trough specimen).

Centrifuge within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​Frozen (preferred) ​28 days
​Refrigerate ​28 days
Rejection Criteria
Gross Hemolysis
​Gross Icterus ​
​Specimens collected in containers other than a Red Top Tube (Plasma, whole blood, SST Tubes are not acceptable) ​
Interference

Toxicity effects other than acute hypersensitivity infusion reactions have not been described nor correlated with infliximab concentrations. 

During the initial induction phase of treatment (weeks 0, 2 and 6), steady-state has not been achieved and concentrations of infliximab may vary significantly between infusions.

Therapeutic concentrations of infliximab may vary according to the disease (eg, Crohn disease vs ulcerative colitis vs rheumatoid arthritis).

Samples containing more than 12.5 ng/mL biotin (vitamin B7) may interfere (in the form of depressed signal) with INXAB / Infliximab Antibodies, Serum.

For antibodies-to-infliximab (ATI), pediatric and adult reference ranges were validated, and the presence of an ATI is established as greater than or equal to 50 U/mL by our bridging electrochemiluminescent/acid dissociation method.

The presence of endogenous infliximab is a recognized interference in most ATI methods. This assay includes an acid dissociation step, which partially mitigates this interference. Tolerance up to 12.5 mcg/mL infliximab has been documented, although this is also determined by the titer of the ATI present in the patient sample

Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories

INFX: Monday, Wednesday, Thursday

INXAB: Monday, Wednesday, Friday

 ​3 days

​INFXR, INFX:  Selective Reaction Monitoring Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

INXAB: Electrochemiluminescent Bridging Immunoassay with Acid Dissociation

Reference Lab
Mayo Clinic Laboratories
Reference Range Information
Performing Location Reference Range
​Mayo Medical Laboratories
INFLIXIMAB QUANTITATION:  Limit of quantitation is 1.0 mcg/mL. Therapeutic ranges are disease specific.
 
Pediatric reference ranges are not established.
 

INFLIXIMAB ANTIBODIES:  Absence of antibodies to infliximab (ATI) is defined as <50 U/mL

Presence of ATI is reported as positive when concentrations are > or =50 U/mL

Interpretation
​Low trough concentrations may be correlated with loss of response to infliximab. For infliximab trough concentrations less than or equal to 5.0 mcg/mL, testing for antibodies to infliximab (ATI) is suggested.
 
For infliximab trough concentrations above 5.0 mcg/mL, the presence of ATI is unlikely; patients experiencing loss of response to infliximab may benefit from an increased dose or a shorter infusion interval.
 
Results above 35 mcg/mL are suggestive of a blood draw at a time-point in treatment other than trough.
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
80230 ​ ​1 ​Infliximab ​
​82397 ​ ​1 ​Infliximab Antibodies ​If needed
Synonyms/Keywords
Remicade, Janssen Biotech, Anti-TNF inhibitor, Auto-immune disease treatment, Inflectra, Pfizer, Inc.
Test Components
Infliximab will be performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on all samples. When Infliximab results are below 5.1 mcg/mL, testing for antibodies to infliximab will be performed at an additional charge.
Ordering Applications
Ordering Application Description
​Centricity ​Infliximab Qnt w/reflex to Infliximab Abs (INFXR)
​Cerner ​Infliximab Qnt w/reflex to Infliximab Abs (INFXR)
​Clinical Order Manager ​Infliximab Qnt w/reflex to Infliximab Abs (INFXR)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Red Top Tube (RTT) ​1 mL ​0.5 mL ​
Collection Processing

​For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.

Draw blood immediately before next scheduled dose (trough specimen).

Centrifuge within 2 hours of collection.

Specimen Stability Information
Specimen Type Temperature Time
​Serum ​ ​Frozen (preferred) ​28 days
​Refrigerate ​28 days
Rejection Criteria
Gross Hemolysis
​Gross Icterus ​
​Specimens collected in containers other than a Red Top Tube (Plasma, whole blood, SST Tubes are not acceptable) ​
Interference

Toxicity effects other than acute hypersensitivity infusion reactions have not been described nor correlated with infliximab concentrations. 

During the initial induction phase of treatment (weeks 0, 2 and 6), steady-state has not been achieved and concentrations of infliximab may vary significantly between infusions.

Therapeutic concentrations of infliximab may vary according to the disease (eg, Crohn disease vs ulcerative colitis vs rheumatoid arthritis).

Samples containing more than 12.5 ng/mL biotin (vitamin B7) may interfere (in the form of depressed signal) with INXAB / Infliximab Antibodies, Serum.

For antibodies-to-infliximab (ATI), pediatric and adult reference ranges were validated, and the presence of an ATI is established as greater than or equal to 50 U/mL by our bridging electrochemiluminescent/acid dissociation method.

The presence of endogenous infliximab is a recognized interference in most ATI methods. This assay includes an acid dissociation step, which partially mitigates this interference. Tolerance up to 12.5 mcg/mL infliximab has been documented, although this is also determined by the titer of the ATI present in the patient sample

Useful For
Trough level quantitation for evaluation of patients with loss of response to infliximab and infliximab-dyyb
Test Components
Infliximab will be performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) on all samples. When Infliximab results are below 5.1 mcg/mL, testing for antibodies to infliximab will be performed at an additional charge.
Reference Range Information
Performing Location Reference Range
​Mayo Medical Laboratories
INFLIXIMAB QUANTITATION:  Limit of quantitation is 1.0 mcg/mL. Therapeutic ranges are disease specific.
 
Pediatric reference ranges are not established.
 

INFLIXIMAB ANTIBODIES:  Absence of antibodies to infliximab (ATI) is defined as <50 U/mL

Presence of ATI is reported as positive when concentrations are > or =50 U/mL

Interpretation
​Low trough concentrations may be correlated with loss of response to infliximab. For infliximab trough concentrations less than or equal to 5.0 mcg/mL, testing for antibodies to infliximab (ATI) is suggested.
 
For infliximab trough concentrations above 5.0 mcg/mL, the presence of ATI is unlikely; patients experiencing loss of response to infliximab may benefit from an increased dose or a shorter infusion interval.
 
Results above 35 mcg/mL are suggestive of a blood draw at a time-point in treatment other than trough.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Medical Laboratories

INFX: Monday, Wednesday, Thursday

INXAB: Monday, Wednesday, Friday

 ​3 days

​INFXR, INFX:  Selective Reaction Monitoring Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

INXAB: Electrochemiluminescent Bridging Immunoassay with Acid Dissociation

Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
80230 ​ ​1 ​Infliximab ​
​82397 ​ ​1 ​Infliximab Antibodies ​If needed
For most current information refer to the Marshfield Laboratory online reference manual.